JPH0762288A - Ink composition for aqueous ball point - Google Patents

Abstract

PURPOSE:To provide the subject composition containing a pigment, an water-soluble organic solvent, a water-soluble resin, a dispersion stabilizer, and water as main components, furthermore containing dibenzylidene sorbitol, having a thixotropic property, not leaking from the tip of the ball point, enabling smooth writing operations, and not generating light color spots. CONSTITUTION:At least 5-10 pts.wt. of a pigment (e.g. carbon black), 10-30 pts.wt. of a water-soluble organic solvent (e.g. diethylene glycol monoethyl ether), 0.5-10 pts.wt. of a water-soluble resin (e.g. carboxymethyl cellulose), 10-30 pts.wt. of additives such as a dispersing agent (e.g. styrene-maleic acid copolymer resin), a surfactant, and an antiseptic, and 0.1-5 pts.wt. of dibenzylidene sorbitol of the formula are added to the remaining amount of water, and subsequently stirred and mixed with each other to obtain the objective aqueous ball point ink composition having a thixotropic property, not requiring an anxiety about the leakage of the ink composition from the tip of the ball point, easily flowing by the rotation of the ball of the ball point, enabling the smooth writing operation of the ball point, and solving problems such as the directional property and light writing spots of the ink composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous ink composition for a ballpoint pen.

[0002]

BACKGROUND OF THE INVENTION Oil-based ballpoint pens
There are drawbacks such as stains on the fingers and writing surface due to ink bots, and great fatigue on the wrist when writing for a long time. The drawbacks of these oil-based ballpoint pens have been solved by the advent of water-based ballpoint pens. That is, since the water-based ballpoint pen has a low viscosity, it has light writing characteristics, dark writing lines, and no fluffing. For this reason, it is beginning to be used in various applications in place of the oil-based ballpoint pen. As an aqueous ink composition for a ballpoint pen, one using a gel-forming polymer substance such as polyvinyl alcohol or carrageenan is known.

[0003]

However, the conventional ink composition is the most suitable for water-based marking pens, brush pens, felt pens, etc. which use batting and utilizes the capillarity, but a ball-point pen having the same structure as an oil-based ball-point pen. It is not suitable for use in. Since it has a low viscosity, there is a problem that ink leaks from the tip of the metal tip, and the ink outflow becomes non-uniform during continuous writing, causing directionality, blurring, and the like.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and as a result, by adding and blending dibenzylidene sorbitol to an aqueous ballpoint pen ink, the ink is given thixotropic properties, The present invention has been completed by finding that there is no fear of leakage and that the ink can easily flow by the rotation of the ball to enable smooth writing, and that problems such as directionality and blurring can be solved. The amount of dibenzylidene sorbitol used in the present invention was 0.1 to 5 parts, and preferably 0.3 to 3 parts, in 100 parts by weight of the ink (hereinafter, the parts are simply referred to as parts). If the amount is less than 0.1 part, the ink viscosity is low, the thixotropic property is weak, and the ink easily leaks. On the other hand, if the amount is 5 parts or more, the thixotropy becomes too strong and the ink outflow becomes poor. In the ink composition for a water-based ballpoint pen of the present invention, the components other than dibenzylidene sorbitol may be the same as those of known water-based ballpoint pen inks.
That is, the ink composition of the present invention comprises 0.1 to 5 parts of dibenzylidene sorbitol, 5 to 10 parts of pigment, 10 to 30 parts of water-soluble organic solvent, 0.5 to 10 parts of water-soluble resin, and surfactant. , 0.05 to 10 parts of appropriate additives such as antiseptics, rust preventives and dispersion stabilizers and / or the balance water. As the pigment used in the present invention, a dispersion stable pigment treated with a polymer composed of a monomer containing both a hydrophilic group and a hydrophobic group in one molecule can be preferably used, such as titanium oxide and carbon black. Inorganic pigment, Carmine 6B,
C. I. Pigment Red 112, C.I. I. Pigment Blue 15, C.I. I. Pigment Green 7 and the like can be exemplified. As the organic solvent used in the present invention, one or more of the following are used. Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1.8-propanediol, 1.3
-Dihydric alcohols such as butylene glycol, 1.4-butanediol, neopentyl glycol, hexylene glycol, thiodiglycol; glycerin, trimethylolethane, trimethylolpropane, diglycerin,
Examples thereof include polyhydric alcohols such as sorbit; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; pyrrolidone; N-methyl-2pyrrolidone. Examples of the water-soluble resin used in the present invention include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxyethyl cellulose, cellulose derivatives such as hydroxypropyl cellulose, dextrin, starch acetate, starch derivatives such as amino starch, sodium alginate, and polyacrylic acid. Examples include soda, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, and carboxyvinyl polymer. The additives used in the present invention include, as surfactants, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, perfluoroalkyl phosphate ester, perfluoroalkyl carboxylate salt. Examples thereof include nonionic surfactants such as, and anionic surfactants such as naphthalenesulfonic acid formalin condensates and perfluoroalkylethylene oxide adducts. Examples of rust inhibitors are benzotriazole, tolyltriazole, dicyclohexylammonium nitrate. Examples of the antiseptic include potassium sorbate,
Examples thereof include sodium benzoate and pentachlorophenol sodium, and examples of the dispersion stabilizer include styrene acrylic resin, styrene maleic acid resin, acrylic methacrylic acid resin and the like. The ink composition of the present invention is
The present invention is not limited to the above composition, and a composition including components other than the above is also included in the scope of the present invention. For example, urea may be further added for the purpose of improving the decapping property.

[0005]

EXAMPLES The ink composition of the present invention is produced, for example, as follows. An ink for a water-based ballpoint pen can be obtained by adding a pigment to a mixed solution containing dibenzylidene sorbitol, a water-soluble resin, a water-soluble organic solvent, water and, if necessary, other additives. In this case, it is preferable to add the pigment while stirring the mixed solution with a high-speed stirrer having a high shearing force such as a homomixer. Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. An ink composition was prepared using each raw material shown in Table 1. Table 2 shows the results of the viscosity, the ink outflow property, the ink leakage, the storage property and the drying property.

[0006]

[Table 1]

An ink composition prepared by using the raw materials shown in Examples and Comparative Examples was filled in a polypropylene ink tank having an inner diameter of 4 mm and a length of 130 mm, and a ball diameter of 0.7
A ball-point pen composed of a 1.5 mm diameter sheep-white tip was formed using a 0.5 mm carbide ball.

[0008]

[Table 2]

Viscosity: Measured at 25 ± 0.5 ° C. with an ELD type rotational viscometer.・ Ink outflow: writing speed 400 cm / mln, writing angle 7
The ink outflow amount when 100 m was written under the condition of 0 ° and a writing load of 100 g was measured.
100 mg and 150 to 200 mg are △, 50 mg or less or 2
00 or more was set as x. -Storability: The state of the ballpoint pen was left at 40 ° C and 60% of humidity, and the clay after 3 months and 12 months was measured. If the increase / decrease in clay is within 10% ○ If it is within 10-15% △ △ If it is 15% or more ・ Ink leakage: Leave the metal tip tip downward at room temperature and leave it for 24 hours. Therefore, there is no ink leakage, and there is leakage. -Dryness of handwriting: After writing Arabic letters 1 to 5 on a high-quality paper, the time until it was dry to the touch was measured. Those dried within 30 seconds were evaluated as ○. Those dried within 30 to 1 minute were evaluated as Δ. It took 1 minute or more as ×. As is clear from Table-2, the ink composition of the present invention comprises
The ink flowability was stable and the storage stability, ink leakage, and handwriting dryness were good, and the ink composition was excellent as an aqueous ink composition for ballpoint pens. When dibenzylidene sorbitol is used outside the range specified in the present invention, if it is too small as in Comparative Example 1, the ink outflow property, ink tip leakage, storage property, and handwriting dryness are poor. If the amount is too large as in Comparative Example 2, the ink outflow is poor. In Comparative Example 3, the ink composition in which polyvinyl alcohol and another water-soluble resin were used in combination without using dibenzylidene sorbitol had poor ink flowability, ink tip leakage, storability, and handwriting dryness.

[0010]

The ink composition of the present invention is characterized by containing dibenzylidene sorbitol.
The ink has thixotropy, and the viscosity of the ink decreases due to the rotation of the ball during writing, so that the ink easily flows and smooth writing becomes possible. In addition, the ink outflow property is stable, the writing line is uniform, and no fluffing occurs during writing. Further, since it has a high viscosity during storage without ball rotation, it has an advantage such as no leakage of the tip.

Claims (1)

[Claims] 1. A dibenzylidene sorbitol represented by the following general formula (1) in an aqueous ink for a ballpoint pen containing at least a pigment, a water-soluble organic solvent, a water-soluble resin, a dispersion stabilizer and water is used. An aqueous ink composition for a ballpoint pen, which contains 5 parts by weight. [Chemical 1]